In some downhole petroleum exploration and recovery operations, fluid is injected into the earthen formation from a perforated base pipe. Because of the potential for flowback of sand or other undesirable material (collectively referred to herein as “debris”) into the base pipe, such as during periods of cessation of fluid injection, a screen assembly is commonly included. When the fluid is injected at high temperatures or velocities, the downhole equipment may be affected by the heated fluid. For example, the injection of high temperature steam in an injection well may cause the base pipe to expand and move longitudinally relative to an associated screen assembly that is confined by the adjacent formation and/or gravel packing. For another example, the high temperature fluid may cause damage or wear to the screen assembly.
There are times when it is beneficial or desirable to vary the injection flow rate or other flow characteristic at different times during the process. This may require or involve changing the size of the orifice(s) through which the fluid, such as steam, is injected through the base pipe. However, changing the injection orifice size typically requires removing the base pipe from its underground site, causing a significant loss of time and efficiency.
It should be understood that the above-described examples, features and/or disadvantages are provided for illustrative purposes only and are not intended to limit the scope or subject matter of the claims of this patent application or any patent or patent application claiming priority hereto. Thus, none of the appended claims or claims of any related application or patent should be limited by the above discussion or construed to address, include or exclude the cited examples, features and/or disadvantages, except and only to the extent as may be expressly stated in a particular claim.
Accordingly, there exists a need for apparatus and methods useful with underground fluid injection systems having one or more of the following attributes, capabilities or features: assists in protecting the screen member from damage due to contact with fluid as it is ejected form the base pipe; assists in protecting the screen member from damage due to contact with fluid as it is ejected from the base pipe even during thermal expansion of the base pipe in either direction; includes at least one deflector to assist in protecting the screen member from damage due to contact with fluid as it is ejected from the base pipe; assists in protecting exit ports in at least one deflector from damage due to contact with fluid as it is ejected from the base pipe; includes a screen that floats on the base pipe to allow longitudinal thermal expansion or other movement of the base pipe relative to the screen; allows longitudinal displacement of the base pipe and/or screen assembly relative to one another; assisting in protecting the fluid flow opening(s) of the base pipe and base pipe from clogging due to sand flowback; includes a remotely replaceable and variable base pipe fluid injection nozzle or choke; includes an isolation flow assembly; allows easily changing the injection orifice size; allows remotely changing the injection orifice size; includes a screen assembly having at least three layers including an outer protective shroud, middle filter media and inner deflector; includes a screen assembly that is robust; includes an inner deflector with a fluid flow port on either or both ends; includes a solid inner deflector with at least one port; includes at least one shear pin to preserve the positional relationship of the screen assembly and base pipe during installation; provides spacing of fluid exit holes along the string to optimize steam injection so that steam may reach the entire interval; is useful as a focus port steam injection well to heat up heavy oil; is capable of being used with steam heated to an example temperature of 330 degrees Celsius; is durable, long lasting and/or low maintenance; or a combination thereof.